The state-of-the-art discloses a coil assembly placed in a U-shaped trough formed in a coil case. The coil case includes at least one U-shaped trough. A quantity of potting material is poured over the entire length of each coil assembly to insulate thereof. The drawback to this assembly method is that the large area of potting material covering the coil assembly is prone to cracking. A coil case with cracked potting material may cause a premature failure of the ignition coil. Cracked potting is also undesirable for numerous other reasons.